Adds AudioDevice factory for all audio clients in Chrome

content/renderer/media/audio_device_factory.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_FACTORY_H_
+#define CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_FACTORY_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "content/common/content_export.h"
+
+namespace media {
+class AudioRendererSink;
+}
+
+namespace content {
+
+// A factory for creating AudioRendererSinks. There is a global factory
+// function that can be installed for the purposes of testing to provide
+// a specialized AudioRendererSink class.
+// This class uses the same pattern as content::RenderViewHostFactory.
+class CONTENT_EXPORT AudioDeviceFactory {
+ public:
+  // Creates an AudioRendererSink using the currently registered factory,
+  // or the default one if no factory is registered. Ownership of the returned
+  // pointer will be passed to the caller.
+ static media::AudioRendererSink* Create();
+
+ protected:
+  AudioDeviceFactory();
+  virtual ~AudioDeviceFactory();
+
+  // You can derive from this class and specify an implementation for this
+  // function to create a different kind of AudioRendererSink for testing.
+  virtual media::AudioRendererSink* CreateAudioDevice() = 0;
+
+ private:
+  // The current globally registered factory. This is NULL when we should
+  // create the default AudioRendererSinks.
+  static AudioDeviceFactory* factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioDeviceFactory);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_FACTORY_H_